examples, initial check in

[SVN r16255]

example/integer.cpp

@@ -0,0 +1,68 @@
+//-----------------------------------------------------------------------------
+// boost mpl/example/integer.cpp source file
+// See http://www.boost.org for updates, documentation, and revision history.
+//-----------------------------------------------------------------------------
+//
+// Copyright (c) 2001-02
+// Aleksey Gurtovoy
+//
+// Permission to use, copy, modify, distribute and sell this software
+// and its documentation for any purpose is hereby granted without fee, 
+// provided that the above copyright notice appears in all copies and 
+// that both the copyright notice and this permission notice appear in 
+// supporting documentation. No representations are made about the 
+// suitability of this software for any purpose. It is provided "as is" 
+// without express or implied warranty.
+
+#include "boost/mpl/arithmetic/multiplies.hpp"
+#include "boost/mpl/list.hpp"
+#include "boost/mpl/lower_bound.hpp"
+#include "boost/mpl/transform_view.hpp"
+#include "boost/mpl/sizeof.hpp"
+#include "boost/mpl/int_c.hpp"
+#include "boost/mpl/identity.hpp"
+#include "boost/mpl/base.hpp"
+#include "boost/mpl/apply_if.hpp"
+#include "boost/mpl/apply.hpp"
+#include "boost/mpl/begin_end.hpp"
+#include "boost/mpl/assert_is_same.hpp"
+
+namespace mpl = boost::mpl;
+using namespace mpl::placeholder;
+
+template< int bit_size >
+class big_int
+{
+    // ...
+};
+
+template< int bit_size >
+struct integer
+{
+    typedef mpl::list<char,short,int,long> builtins_;
+    typedef typename mpl::base< typename mpl::lower_bound<
+          mpl::transform_view< builtins_
+            , mpl::multiplies< mpl::sizeof_<_1>, mpl::int_c<8> >
+            >
+        , mpl::int_c<bit_size>
+        >::type >::type iter_;
+
+    typedef typename mpl::end<builtins_>::type last_;
+    typedef typename mpl::apply_if<
+          boost::is_same<iter_,last_>
+        , mpl::identity< big_int<bit_size> >
+        , mpl::apply0<iter_>
+        >::type type;
+};
+
+typedef integer<1>::type int1;
+typedef integer<5>::type int5;
+typedef integer<15>::type int15;
+typedef integer<32>::type int32;
+typedef integer<100>::type int100;
+
+BOOST_MPL_ASSERT_IS_SAME(int1, char);
+BOOST_MPL_ASSERT_IS_SAME(int5, char);
+BOOST_MPL_ASSERT_IS_SAME(int15, short);
+BOOST_MPL_ASSERT_IS_SAME(int32, int);
+BOOST_MPL_ASSERT_IS_SAME(int100, big_int<100>);